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The energy storage and vehicle industries are heavily investing in advancing all-solid-state batteries to overcome critical limitations in existing liquid electrolyte-based lithium-ion batteries, specifically focusing on mitigating fire hazards and improving energy density. All-solid-state lithium–sulfur batteries (ASSLSBs), featuring earth-abundant sulfur cathodes, high-capacity metallic lithium anodes, and non-flammable solid electrolytes, hold significant promise. Despite these appealing advantages, persistent challenges like sluggish sulfur redox kinetics, lithium metal failure, solid electrolyte degradation, and manufacturing complexities hinder their practical use. To facilitate the transition of these technologies to an industrial scale, bridging the gap between fundamental scientific research and applied R&D activities is crucial. Our review will address the inherent challenges in cell chemistries within ASSLSBs, explore advanced characterization techniques, and delve into innovative cell structure designs. Furthermore, we will provide an overview of the recent trends in R&D and investment activities from both academia and industry. Building on the fundamental understandings and significant progress that has been made thus far, our objective is to motivate the battery community to advance ASSLSBs in a practical direction and propel the industrialized process. [ABSTRACT FROM AUTHOR]

The electrochemical performance, reliability, and safety of Li-ion cells depend on thermal management. However, the heat generation mechanisms and release characteristics of large-format high-energy-density (HED) Li-ion cells, a prerequisite for an efficient battery thermal management system (TMS), remain unclear. This study clarifies the heat issues of a 57.5 Ah HED (266.9 W h kg−1) Li-ion cell with a promising material couple of nickel-rich cathode and SiOx/graphite anode. Both reversible entropic heat and irreversible polarization heat at different discharge rates are unraveled. While charge transfer and mass transport dominate the total polarization heat, the contribution from the ohmic effect and surface impedance increases with discharge rates. Polarization heat also increases consistently with lowering SOCs because of the increasing mass transport overpotential. In particular, the abrupt increase of heat generation at a SOC below 25% may be due to the leveraged discharge rate of SiOx caused by the mismatch of the voltage windows of graphite and SiOx. Moreover, the isothermal calorimetry study uncovers the significant heat accumulation and delayed heat release effects of large-format cells, which could cause undetectable but dangerous internal temperature rise at high discharge rates. Findings obtained in this study could guide the rational design of HED cells and TMS optimization. [ABSTRACT FROM AUTHOR]

Herein, we report a post-assembly strategy by growing bimetallic Co/Zn zeolitic imidazolate frameworks (BIMZIF) on the surface of customized Mo metal–organic frameworks (MOFs) (Mo-MOFs) to prepare core–shell structured Mo-MOF@BIMZIF, which results in a porous Co–MoO2 polyhedral nanocage (Co–MoO2-NC) structure and abundant Co–Mo–O active sites after high temperature pyrolysis. Co–MoO2-NC-900 which was obtained by pyrolysis at 900 °C displays a low overpotential (370 mV) for the oxygen evolution reaction (OER) and a half-wave potential (E1/2 ≈ 0.89 V) for the oxygen reduction reaction (ORR), exhibiting bifunctional features. A Zn–air battery with Co–MoO2-NC-900 shows a high power density of 176.5 mW cm−2 at 217.1 mA cm−2, which is better than that of reference Pt/C + Ir/C electrocatalysts, and is capable of exhibiting a smaller discharge–charge overpotential (0.85 V) and excellent stability (1145 h). Density functional theory calculations and experiments reveal that the structure and electron transfer between the Co and MoO2 components reduce the free energy of the intermediates, resulting in bifunctional electrocatalytic activity. [ABSTRACT FROM AUTHOR]

Energy storage and conversion systems, including batteries, supercapacitors, fuel cells, solar cells, and photoelectrochemical water splitting, have played vital roles in the reduction of fossil fuel usage, addressing environmental issues and the development of electric vehicles. The fabrication and surface/interface engineering of electrode materials with refined structures are indispensable for achieving optimal performances for the different energy-related devices. Atomic layer deposition (ALD) and molecular layer deposition (MLD) techniques, the gas-phase thin film deposition processes with self-limiting and saturated surface reactions, have emerged as powerful techniques for surface and interface engineering in energy-related devices due to their exceptional capability of precise thickness control, excellent uniformity and conformity, tunable composition and relatively low deposition temperature. In the past few decades, ALD and MLD have been intensively studied for energy storage and conversion applications with remarkable progress. In this review, we give a comprehensive summary of the development and achievements of ALD and MLD and their applications for energy storage and conversion, including batteries, supercapacitors, fuel cells, solar cells, and photoelectrochemical water splitting. Moreover, the fundamental understanding of the mechanisms involved in different devices will be deeply reviewed. Furthermore, the large-scale potential of ALD and MLD techniques is discussed and predicted. Finally, we will provide insightful perspectives on future directions for new material design by ALD and MLD and untapped opportunities in energy storage and conversion. [ABSTRACT FROM AUTHOR]

Pt catalysts are the best potential hydrogen evolution reaction (HER) electrocatalysts for industrial applications, but the development of efficient Pt catalysts with low Pt loading and high utilization efficiency remains challenging. Herein, sub-nanometer PtCo clusters confined into the small pores of ZIF-8 derived N-doped nanomaterials are fabricated through the galvanic replacement method. Benefiting from the formation of sub-nanometer PtCo clusters confined in small pores and the synergic effect of bimetallic components, the optimal sub-nanometer PtCo clusters with only 1.2% Pt loading (1.2%PtCo/NPC) achieve an extraordinary HER catalytic activity and durability with a mass activity of 13.83 A mg−1 at an overpotential of 20 mV, which is more than 65 times greater than that of the commercialized Pt/C catalyst. Density functional theory (DFT) calculations reveal that the outstanding HER activity on the 1.2%PtCo/NPC electrocatalyst is attributed to the charge redistribution and the lower d-band center on Pt due to the enhanced coupling of electrons in the d orbitals between Pt and Co, which decreases the Gibbs free energy of H* adsorption and increases the HER kinetics and activity. [ABSTRACT FROM AUTHOR]

Graphynes (GYs) are the new star carbon isomers with two-dimensional layered in-plane porous structures, which are composed of sp- and sp2-hybrid carbon atoms. These special features result in their unique topological and electronic structures, high charge mobility and excellent electronic transport properties. All of these advanced properties of GYs make them promising in various applications. In the GY family, graphdiyne (GDY) was the first successfully prepared member, so it attracted the most attention. In this review, the recent progress on the synthetic strategies, functional mechanisms and applications of GDY and other GYs in the fields of energy storage/conversion are summarized, and the challenges hindering their large-scale fabrication toward practical applications are analyzed. Finally, the possible research directions for overcoming the challenges are proposed based on the development trend and perspectives of GYs. It is hoped that this review is helpful for deeply understanding GYs and GY-based materials. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed cross-coupling reaction of aryl halides with 2-chlorobenzoic acids has been developed. The reaction forms C(sp3), C(sp2)-palladacycles through C(sp3)–H activation. The palladacycles react with 2-chlorobenzoic acids through two successive C–C cross-couplings, and two C–C bonds are formed with high chemoselectivity. The reaction provides an innovative method for the synthesis of 9,10-dihydrophenanthrenes. [ABSTRACT FROM AUTHOR]

Metal–support interaction (MSI) holds great promise for the development of heterogeneous catalysts. Accordingly, it is essential to implement facile methods to modulate MSI for the improvement of catalytic performance. In this study, an effective method is proposed to directly enhance MSI, wherein the electronic properties of Pt are altered by the ion-exchanging reaction of the support, affording incredible catalytic performance. Pt nanoparticles with 1.5 nm diameters are successfully deposited on a quasi-layered sodium titanate support via atomic layer deposition (ALD). The ion-exchanging reaction of the support between the Na-ions and H-ions in acidic media results in the transformation of the support structure, and further modulates the Pt local electronic structure. Such behaviour facilitates the enhancement of MSI offering highly active and stable Pt sites. The as-prepared catalyst exhibits much higher mass activity and long-term stability for the hydrogen evolution reaction (HER) in comparison with Pt/TiO2 and commercial Pt/C. The enhancement mechanism of MSI comes through the structural variation of the support, with modified charge transfer between the Pt and its support. Moreover, this new approach provides a facile and reliable path to develop advanced catalysts with enhanced MSI and motivates further research in many fields. [ABSTRACT FROM AUTHOR]

Solid-state lithium–sulfur batteries (SSLSBs) with high energy densities and high safety have been considered among the most promising energy storage devices to meet the demanding market requirements for electric vehicles. However, critical challenges such as lithium polysulfide shuttling effects, mismatched interfaces, Li dendrite growth, and the gap between fundamental research and practical applications still hinder the commercialization of SSLSBs. This review aims to combine the fundamental and engineering perspectives to seek rational design parameters for practical SSLSBs. The working principles, constituent components, and practical challenges of SSLSBs are reviewed. Recent progress and approaches to understand the interfacial challenges via advanced characterization techniques and density functional theory (DFT) calculations are summarized and discussed. A series of design parameters including sulfur loading, electrolyte thickness, discharge capacity, discharge voltage, and cathode sulfur content are systematically analyzed to study their influence on the gravimetric and volumetric energy densities of SSLSB pouch cells. The advantages and disadvantages of recently reported SSLSBs are discussed, and potential strategies are provided to address the shortcomings. Finally, potential future directions and prospects in SSLSB engineering are examined. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries (SIBs) are promising low-cost alternatives to lithium-ion batteries (LIBs) in energy storage applications because of the natural abundance of sodium as compared with lithium. However, the radius of Na+ ions is ∼50% larger than that of Li+ ions, leading to challenging sodiation/desodiation at the anodes of SIBs and reduced performances. Therefore, the exploration of novel SIB anode materials to facilitate sodiation/desodiation has become a leading area of research. Here, cost-effective phosphorus and metal/nonmetal phosphides, possessing high theoretical gravimetric capacities and volumetric specific capacities, have emerged as new and promising anode materials for SIBs. Based on this, this review will provide a comprehensive summary of the recent progress in the development of phosphorus and metal/nonmetal phosphide materials and corresponding composite SIB anodes in terms of material synthesis, characterization, sodium storage mechanism and performance validation in SIB apparatuses. In addition, challenges associated with the development of such advanced materials are summarized and analyzed. Finally, to facilitate the research and development of these emerging SIB anode materials, future research directions are proposed to overcome challenges toward the practical commercialization of sodium-ion batteries. [ABSTRACT FROM AUTHOR]

All-solid-state lithium batteries (ASSLBs) are promising energy storage devices for application in electric transportation and large-scale energy storage systems. Polyethylene oxide (PEO)-based solid polymer electrolytes (SPEs) are attractive solid-state electrolytes for ASSLBs due to their high ionic conductivity, light weight, and low cost. However, the low electrochemical oxidation potential window of PEO seriously restricts its implementation with high voltage cathodes for high-energy-density ASSLBs. Effective interfacial engineering between high voltage cathodes and SPEs can be a solution. Most of the reported conventional cathode protection approaches have been focused on building coating layers on active material particles, which, however, can be insufficient because the conductive carbon is able to accelerate the decomposition of SPEs. In this work, atomic layer deposition (ALD) coating on the electrode instead of active material particles realizes a unique method to protect the cathode/SPE interface. As a successful example, a thin ALD-derived lithium tantalate coating on the high-voltage LiCoO2 electrode demonstrated good compatibility with PEO-based SPEs, significantly enhancing the cycling performance of the ASSLBs. The inner mechanism is attributed to the fact that the protection of the conductive carbon/SPE interface helps reduce the electrochemical oxidation of PEO-based SPEs. This work shall give new insights for the interfacial engineering of high voltage cathodes and solid polymer electrolytes. [ABSTRACT FROM AUTHOR]

In this work, Pt3Sn–SnO2 supported on N-doped graphene (Pt3Sn–SnO2/NG) was synthesized through the in situ transformation of Pt–Sn/NG by annealing in an air atmosphere. The Pt3Sn–SnO2/NG catalyst, characterized by XRD, TEM and HRTEM, forms an ordered Pt3Sn intermetallic in which every Pt3Sn nanoparticle (NP) is in close contact with one or more SnO2 NPs. The Pt3Sn–SnO2/NG catalyst shows outstanding performance towards the ethanol oxidation reaction (EOR) and methanol oxidation reaction (MOR). The mass activity for EOR on the Pt3Sn–SnO2/NG catalyst is 469 mA mgPt−1 at 0.7 V, which is more than 10 times that of the commercial Pt/C catalyst (44 mA mgPt−1). The Pt3Sn–SnO2/NG catalyst is found to have more than three times the stability of the commercial Pt/C. Our Pt3Sn–SnO2/NG catalyst also delivers increased activity and higher stability for MOR compared with the Pt/C catalyst. In addition, the Pt3Sn–SnO2/NG catalyst is observed to have a higher CO tolerance compared with Pt/C. The high activity and stability of the Pt3Sn–SnO2/NG catalyst can be attributed to the unique structure of Pt3Sn–SnO2, formed by the in situ transformation of Pt–Sn/NG, which induces the formation of a small-sized ordered Pt3Sn intermetallic that strongly interacts with SnO2. The synergetic effect between the ordered Pt3Sn and SnO2 enhances the activity towards EOR and MOR through the Sn in both Pt3Sn and SnO2, which facilitates the removal of COads on the adjacent Pt active sites at low potentials by providing OHads species; it also improves stability because of the strong Pt3Sn–SnO2 interactions. [ABSTRACT FROM AUTHOR]

Quasi-solid-state lithium–selenium batteries (QSSLSEBs) assembled with gel polymer electrolytes (GPEs) are a promising class of next-generation rechargeable batteries due to their safety, high energy density and shuttle-free charging/discharging process. Nevertheless, both poor Li+ transport in thick electrodes and Li dendrite growth limit the improvements of the current density as well as Se loading, resulting in low energy/power densities. Herein, we proposed to combine a 3D-printed carbon nanotube (CNT) interlayer to protect the Li anode with a 3D-printed Se cathode (named 3DPSe) filled with GPEs in high Se loading cathodes to achieve ultra-high energy/power-density QSSLSEBs. Benefitting from the 3D-printed CNT interlayer in suppressing Li dendrite growth, the Li–Li symmetric cell stably runs for 400 h (3 mA cm−2; 3 mA h cm−2), which is almost one order of magnitude longer than the interlayer-free cell. Moreover, 3DPSe acts as a host for GPE impregnation to fabricate interconnect Li+ transport channels in the thick Se cathode, enabling fast Li+ transport. Accordingly, the QSSLSEB assembled with an ultra-high Se loading of 20 mg cm−2 delivers the highest reported areal capacity of 12.99 mA h cm−2 at 3 mA cm−2. This work is expected to open up promising opportunities to develop other high-energy/power-density solid-state lithium batteries (SSLBs). [ABSTRACT FROM AUTHOR]

Developing stable nanocatalysts with high activity for the oxygen reduction reaction (ORR) remains a great challenge in the field of clean energy. Herein, a highly stable and active nanocatalyst is designed by an efficient dealloying of Pt–Ni nanowires in an oxygen saturated solution. It is found that Ni atoms can be removed almost completely in an oxygen atmosphere (D-O2–Pt NWs) instead of an Ar environment, confirmed by a combination of X-ray diffraction, X-ray photoelectron spectroscopy and surface-sensitive electrochemical characterization methods. As a result, the D-O2–Pt NWs exhibit an enhanced mass (0.86 A mgPt−1) and specific (0.99 mA cmPt−2) activity compared to commercial Pt/C for the ORR by a factor of 5 and 5.8, respectively. These catalysts also show an increased power density (30%) and polarization current density (50%) at 0.5 V of real H2/air PEMFCs with respect to commercial Pt/C. In addition, in contrast to the 60% activity loss of Pt/C after accelerated degradation tests (ADTs) for 50 000 potential cycles, the D-O2–Pt NWs show an extremely stable behavior with only 17% performance loss. The high activity and extreme stability of D-O2–Pt NWs are rationalized by the structural effects, confirmed by the combination of quantitative analysis using X-ray absorption fine structure (XAFS), high resolution-transmission electron microscopy (HR-TEM) and average adsorbed CO oxidation potential (μ CO1). This work illustrates a new class of Pt based nanocatalysts with high activity and stability for the ORR. [ABSTRACT FROM AUTHOR]

Safe, high-energy-density and long-life Li metal batteries (LMBs) are highly attractive as a power source. However, the development of LMBs encounters serious challenges due to the formation of Li dendrites and the leakage and flammability of organic liquid electrolytes. Herein, a novel nanowire-film-reinforced hybrid gel polymer electrolyte (HGPE) is developed. The interconnected porous nanowire film as the backbone not only strengthens the mechanical structure of GPEs but also ensures the continuity for Li+ conduction. The designed HGPE can simultaneously achieve the suppression of Li dendrites and high ionic conductivity (1.04 × 10−3 S cm−1). The films with controllable thicknesses offer the ability to prepare ultrathin HGPEs with great mechanical properties. With these merits, the Li metal symmetric cells exhibit significantly enhanced cycling stability for over 2100 h with low overpotential. The Li–O2 battery using the HGPE also delivers an ultralong cycle life of up to 494 cycles. The present study may open a new window for reinforcing GPEs and offer an opportunity for developing quasi-solid-state LMBs. [ABSTRACT FROM AUTHOR]

The pressure-induced crystallization of amorphous red phosphorus to black phosphorus was investigated by in situ Raman spectroscopy and high resolution transmission electron microscopy. Raman measurements revealed slow crystallization kinetics. The morphology and crystal structural analysis provided detailed information on nucleation and crystal growth as well as the crystallization mechanism. [ABSTRACT FROM AUTHOR]

Carbon materials usually exhibit a low capacity, short cycle life and poor rate performance as anode materials for lithium ion batteries (LIBs) and sodium ion batteries (SIBs). It remains a great challenge to explore carbon materials for ultrafast lithium and sodium storage with both a high capacity and a long cycling stability. Herein, we report the fabrication of nitrogen (N)/oxygen (O) dual dopant hollow porous carbon nanocapsules that show a state-of-the-art electrochemical performance. If used as anodes for LIBs, at an ultrahigh current density of 30 A g−1, the carbon nanocapsules can be cycled up to 11 000 cycles with a considerable capacity retention of ∼310 mA h g−1. For sodium storage, they also demonstrate an ultrastable cycling performance with a reversible capacity of ∼150 mA h g−1 after 10 000 cycles at a high current density of 5 A g−1. The outstanding electrochemical performance can be ascribed to the synergistic effects from heteroatom doping and the unique sealed porous hollow characteristics of the nanocapsules. Theoretical calculations suggest that the sealed capsule structure leads to a excellent mechanical stability, which can tolerate fast lithium/sodium intercalation and extraction at ultrahigh current densities. [ABSTRACT FROM AUTHOR]

The ultrafast ionic conductivity of Li6PS5Br, which is higher than 1 mS cm−1 at room temperature, makes it an attractive candidate electrolyte for the all-solid-state Li–S battery. A simple synthesis route with an easy scale up process is critical for practical applications. In this work, the highest room temperature ionic conductivity (2.58 × 10−3 S cm−1) of Li6PS5Br is obtained by an optimal annealing temperature in a simple solid-state reaction method. Neutron diffraction and XRD show that the origin of the highest ionic conductivity is due to the higher purity, smaller mean lithium ion jumps and the optimal Br ordering over 4a and 4c sites. All-solid-state Li–S batteries using a S–C composite cathode in combination with the optimized Li6PS5Br electrolyte and Li–In anode show high (dis)charge capacities. Different cycling modes (charge–discharge and discharge–charge) reveal that the capacity of the S–C–Li6PS5Br/Li6PS5Br/Li–In battery arises from both the active S–C composite and the Li6PS5Br in the cathode mixture. The contribution of the latter is verified from all-solid-state batteries using Li6PS5Br and its analogues as active materials. Ex situ XRD and electrochemical performance results show that the contribution of capacity from Li6PS5Br in the cathode mixture may be associated with the decomposition product Li2S, while the Li6PS5Br in the bulk solid electrolyte layer is stable during cycling. [ABSTRACT FROM AUTHOR]

We report a hollow carbon nanopolyhedron catalyst doped with N and single Fe atoms, prepared by pyrolyzing hollow ZIF-8 with ferric acetylacetonate and g-C3N4. The catalyst retains the polyhedral morphology of its precursor and possesses exclusively Fe–N4 moieties promoted by g-C3N4 nitriding, evidenced by multipronged microscopic and spectroscopic analyses. In rotating disk measurements, the catalyst exhibits superior ORR activity in both acidic and alkaline media, with a half-wave potential of 0.78 V in the former and 0.845 V in the latter. In addition, its ORR stability surpasses that of commercial Pt/C in acidic and alkaline media. Most notably, the catalyst exhibits ultra-high performance in a H2/O2 proton exchange membrane fuel cell (PEMFC), with a current density of 400 mA cm−2 at 0.7 V and 133 mA cm−2 at 0.8 V, and a maximum power density of 628 mW cm−2. This is among the best PEMFC performances reported for cathodes free of platinum-group metals. We attribute this excellent-ORR activity to the integration of the high density Fe(ii)–N4–H2O moiety (4.51956 × 1013 sites cm−2) embedded in the carbon framework, identified by in situ X-ray absorption spectroscopy, and the well-balanced micro/meso/macroporous structure. [ABSTRACT FROM AUTHOR]

Na metal is considered as a promising anode material for Na metal batteries (NMBs) due to its high theoretical specific capacity and low electrochemical potential. However, the Na metal anode faces several challenges, including: (1) safety concerns related to dendrite formation; (2) low coulombic efficiency (CE) and poor cycling performance caused by the unstable solid electrolyte interphase (SEI); (3) an infinite volume change due to its hostless nature. In this paper, we demonstrate for the first time a facile and in situ solution-based method to synthesize an artificial protective layer of Na3PS4 (NaPS) on the surface of Na metal. Promisingly, the thickness and composition of the NaPS can be controlled through adjustment of the precursor concentration and reaction times. The thin amorphous NaPS layers on the surface of the Na metal will reduce parasitic side reactions with electrolyte components, increase the homogeneity of the SEI layer and improve the Na+ flux on the surface. Meanwhile, the ionically conductive NaPS can eliminate the strong electric field buildup at the surface, resulting in a more homogeneous Na plating/stripping process with suppressed Na dendrite growth. The design of the NaPS-coated Na anode opens up new opportunities for the realization of next-generation high-energy density Na metal batteries. [ABSTRACT FROM AUTHOR]

The electrochemical hydrogen evolution reaction (HER) is an emerging route for producing clean hydrogen. Recently, Ru-based catalysts have exhibited good activity towards the HER, making them attractive substitutes for Pt. However, the HER performance of Ru-based catalysts still cannot reach the same level as that of commercial Pt/C in acid solution. The atomic layer deposition (ALD) technique has proved to be an effective route for the preparation of noble metal catalysts on substrates. Herein, we successfully deposited RuOx catalysts on octahedral and cubic Pd seeds through an ALD process. Interestingly, we found that RuOx was selectively deposited on Pd particles when Pd/nitrogen-doped carbon nanotubes (NCNTs) were used as the substrate. Importantly, the as-prepared Pd@RuOx/NCNT showed comparable activity with state-of-the-art commercial Pt/C catalysts for the HER. The performance exceeds all of the current Ru-based nanocatalysts for the HER in acid solution. The X-ray absorption spectroscopy and X-ray photoemission spectroscopy analyses indicated that the RuOx shell consists of metallic Ru and Ru(iv). Density functional theory calculation results indicated that the Gibbs free energy of the intermediate state H* of octahedral Pd@RuOx was much lower than that of cubic Pd@RuOx, which resulted in the superior HER activity. This paper provides an example for the rational design of efficient catalysts through a combination of shape-controlled synthesis and the ALD technique. [ABSTRACT FROM AUTHOR]

All-solid-state lithium–sulfur batteries (ASSLSBs) are promising candidates as the power source for future electric vehicles due to their high energy density and superior safety properties. However, one of the major challenges of state-of-the-art ASSLSBs is related to the high interfacial resistance resulting from the instability between the solid-state electrolyte (SSE) and electrodes and/or the side reactions between polysulfides and SSE. Herein, we propose and demonstrate the significant enhancement of the cycling stability of an ASSLSB through atomic layer deposition interfacial engineering on the polymer/oxide ceramic/polymer sandwich-structured SSE. The results show that as few as 10 cycles of ALD Al2O3 on the LATP can endow ASSLSBs with a discharge capacity of 823 mA h g−1 after 100 charge/discharge cycles, which is almost two times higher than that of the ASSLSB without an ALD coating and that of a Li–S battery with a liquid-based electrolyte. Such improvement is attributed not only to the blocking of the polysulfide shuttling effect via the use of a sandwich SSE but also the significant reduction of the side reaction between the polysulfide and oxide ceramic SSE, which introduces high interfacial resistance and degrades the electrochemical performance. The protection role and mechanism of the ALD layer is also confirmed and revealed by XRD, SEM and XPS measurements. [ABSTRACT FROM AUTHOR]

The rational design of cathode hosts with superior polysulfide (PS) confinement properties, excellent Li+/e− transport and improved cyclability is of the utmost importance for high-areal-capacity lithium–sulfur (Li–S) batteries. Herein, multi-functional nanowall arrays (MNWAs) combining the aforementioned properties are fabricated to improve the electrochemical performance of Li–S batteries with high areal sulfur loadings. The integrated conductive networks and top-down vertically aligned Li+ transport channels are beneficial to Li+/e− transport, resulting in high rate performance with a discharge capacity of 620 mA h g−1 at a high current density of 9.6 mA cm−2 for 4 mg cm−2 sulfur-loaded S/MNWA electrodes. Additionally, the strong PS shuttling suppression via the synergetic effects of physical confinement and chemical adsorption leads to Li–S batteries with a sulfur loading of 10 mg cm−2 capable of delivering a high areal capacity of 12.4 mA h cm−2 with a high capacity retention of nearly 85% for over 100 cycles. What's more, the Li–S batteries assembled with 4 mg cm−2 sulfur-loaded S/MNWA electrodes show an ultra-low capacity decay of 0.07% per cycle over 400 cycles at 3.2 mA cm−2. [ABSTRACT FROM AUTHOR]

Developing sodium based energy storage systems that retain high energy density at high power along with stable cycling is of paramount importance to meet the energy demands of next generation applications. This requires the development of electrodes beyond the conventional intercalation-based chemistry to overcome the sluggish diffusion-limited reaction kinetics and limited cycle life. Herein, we report a rationally designed hollow graphene nanosphere (HGS) cathode, which utilizes non-destructive, ultra-fast surface redox reactions at oxygen functional groups and delivers a discharge capacity of ∼155 mA h g−1 (0.1 A g−1) corresponding to a high energy of ∼415 W h kg−1 and retains ∼88 W h kg−1 of energy at a remarkable specific power of ∼84 kW kg−1 (40 A g−1), which are beyond the capabilities of intercalation-based electrodes. Moreover, the achieved cycling performance (86% capacity retention after 50 000 cycles at 10 A g−1) is the most stable cathode performance reported so far. The rationally designed sodium metal battery full cells with a sodium metal deposited aluminium current collector anode and the HGS cathode showed a similar sodium ion storage performance with high capacity, good rate capability, and stability. We certainly believe that the current research could direct the future research development towards transition metal-free, ultra-high power and super stable cathodes for sodium energy storage devices. [ABSTRACT FROM AUTHOR]

Sodium–air batteries are attracting increasing research interest due to their high theoretical energy density and environmentally benign characteristics. Although sodium–air batteries share a similar concept, design, and composition when compared with their lithium–air counterparts, they still show many differences in their electrochemical behaviors and mechanisms. In the present work, the employment of four different types of polymers as binders in air electrodes for sodium–air batteries is presented, while the electrochemical and physical characterizations are carried out. Insights into how polymer binders impact the reaction mechanisms and formation of superoxide/peroxide species of sodium–air batteries from the view of their functional groups are revealed. [ABSTRACT FROM AUTHOR]

Exploitation of high capacity and long-life anode materials is essential for the development of lithium-ion batteries (LIBs) with high energy density. Metal sulfides have shown great potential as anode materials for LIBs due to their high theoretical specific capacity and excellent electronic properties and therefore they are considered as excellent candidates for anode materials. However, structural degradation during cycling and polysulfide dissolution has limited their practical application. In this work, we design a unique 0D/1D heterostructure of carbon coated iron–nickel sulfide nanodots/carbon nanorod through simultaneous decomposition and sulfidation of a bi-metal organic framework template. The resultant nanodots/nanorod heterostructure allows for fast ion/electron transport kinetics, suppresses polysulfide dissolution and ensures structural integrity during the lithiation/delithiation process. Consequently, this carbon coated iron–nickel sulfide nanodots/carbon nanorod structure exhibits a high specific capacity (851.3 mA h g−1 at 0.5C after 200 cycles) and an excellent cycling stability (484.7 mA h g−1 after 1000 cycles at a high rate of 4C). [ABSTRACT FROM AUTHOR]

Carbon nanofibers (CNFs) belong to a class of one-dimensional (1D) carbonaceous materials with excellent electronic conductivity, leading to their use as conductive additives in electrode materials for lithium-ion batteries (LIBs) and sodium-ion batteries (NIBs). Additionally, CNFs show excellent lithium- and sodium-storage performance when used directly as anode materials via template and activation strategies to produce numerous intercalation sites. In the case of the non-carbon electrodes for LIBs & NIBs, CNFs are capable of functioning as electron conducting and porous substrates to enhance the overall electronic & ionic conductivity and stabilizing the structures of electrodes during cycling, facilitating the improvement of the electrochemical performance of non-carbon anode and cathode materials. In this review, we present a comprehensive summary of the recent progress of CNF application in LIBs and NIBs, focusing on the structural evolution and the resulting improvements in electrochemical performance and demonstrating the importance of advancements in CNF-based electrode materials. [ABSTRACT FROM AUTHOR]

Porous carbon nanospheres have received enormous attention due to their various applications. Although several elegant strategies exist for the synthesis of relatively large carbon nanospheres (＞ca. 100 nm), the synthesis of carbon nanospheres with well-defined, tunable ultra-small sizes (＜50 nm) has often been challenging, while such ultra-small nanospheres are much more valuable. A novel, convenient and scalable catalytic emulsion polymerization technique is demonstrated in this paper for the highly efficient synthesis of ultra-small carbon nanospheres with uniform tunable sizes in the range of 11–38 nm. In this strategy, a simple change in the emulsion polymerization recipe renders a convenient yet efficient tuning of the size of the carbon nanospheres. In particular, activated carbon nanospheres (A-CNS21 with an average size of 21 nm), obtained by carbonization in the presence of KOH as the chemical activation agent, possess a very high surface area (2360 m2 g−1) and desired hierarchical macro-/meso-/micropore structures which result from nanosphere packing/aggregation. A-CNS21 is demonstrated to exhibit superior high-rate supercapacitive performance and outstanding sorption capacities towards volatile organic compounds (VOCs), H2 and CO2, which are comparable to or even better than the best results reported to date in these applications. To the best of our knowledge, this is the first synthesis of ultra-small carbon nanospheres, with uniform tunable sizes and superior performance for these applications, by the emulsion polymerization strategy. [ABSTRACT FROM AUTHOR]

Tantalum oxide (TaOx) nanoparticles (NPs) are deposited on a commercial Pt/C catalyst by an area-selective atomic layer deposition (ALD) approach to enhance the stability of the catalyst in proton exchange membrane fuel cells (PEMFCs). Due to the application of a blocking agent for protecting the Pt surface, TaOx particles are selectively nucleated and grown around Pt NPs. The TaOx loading on the Pt/C surface could be controlled precisely by varying the number of ALD cycles. When deposited on the Pt/C surface with 35 ALD cycles, the TaOx-anchored Pt NPs formed an excellent triple-junction structure of TaOx–Pt–carbon. The electrochemical durability tests indicated that the TaOx-anchored Pt/C catalyst showed comparable catalytic activity and superior long-term stability to Pt/C. Moreover, the long-term stability test in membrane electrode assembly (MEA) indicated a very low power density loss (12%) after a 120 h accelerated durability test. The significantly enhanced catalyst stability during PEMFCs operation is due to the anchoring effect of TaOxvia strong metal oxide–support interactions. This strategy shows great potential for developing highly stable catalysts for PEMFCs. [ABSTRACT FROM AUTHOR]